The Study about P-Δ Effect of Vertical Ground Motion in Near-fault
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摘要: 竖向效应是近断层地震动的主要特点,竖向地震动对工程结构形成的P-Δ效应是造成结构破坏的主要原因。本文以单自由度体系为研究对象,选取汶川地震的近断层强震数据进行研究,分析竖向地震动所产生P-Δ效应的放大作用特征。分析结果表明汶川地震中,相比于中远场区域,近断层区域内竖向地震动作用所产生的P-Δ效应具有明显的放大作用,且近断层内这种放大作用具有普遍性;当自振周期一定时,不同台站获得地震动的放大系数离散性较小,主要分布于均值附近;其分析结果符合地震动的一般规律,分析结果合理。在此基础上建立了以均值为代表值的放大系数谱,可以与抗震设计反应谱结合使用,从而为活断层附近区域内的结构抗震设计问题提供定量化参考依据。Abstract: Vertical effect is the main characteristic of ground motion in near fault, and the P-Δ effect caused by vertical ground motions is the main reason for the failure of engineering structures. In this paper, taking the single degree of freedom system as the object, strongmotion datum of Wenchuan earthquake in near fault region were selectedto study the amplification characteristics of P-Δ effect for vertical seismic action. Our results show that P-Δ effect caused by vertical ground motions had the obvious amplification which were universal in near-fault region of the Wenchuan earthquake. In comparing with the region of medium-field and far-field, amplification of ground motions obtained from different stations did not discrete very much and distributed near mean values. The analytic results accord with the general law of ground motion. Based on this, the amplification spectra which can be applied in seismic response spectra were built, and the quantitative criterion for structural seismic design in near-fault region was put forward.
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Key words:
- Near-fault /
- P-Δ effect /
- Amplification /
- Natural period /
- Amplification spectra
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表 1 所选取强震记录的近场台站信息
Table 1. The information of near-site stations selected in the study
编号 51MZQ 51JYH 51PXZ 51AXT 51JYD 51SFB 51MXN 51WCW 51MXT 51JYC 断层距/km 7.17 13.6 21.05 25.89 26.43 26.73 27.09 27.72 27.77 30.54 编号 51DXY 51DYB 51LXT 51QLY 51LXM 51PWM 51LXS 51GYZ 51BXZ 51XJD 断层距/km 31.19 34.33 46.4 49.17 49.18 51.28 51.58 55.15 57.75 59.09 表 2 所选取强震记录的中远场台站信息
Table 2. The information of remote stations selected in the study
编号 51HSD 51CXQ 51YAS 51JZB 62SHW 51JZZ 51TQL 51HYQ 51HYJ 51LDD 断层距/km 104.5 104.7 111.1 114.2 121.1 125.4 137.2 155.4 163 177.1 编号 51SMW 51LDL 62TSH 51SMM 51MBD 51YXX 51YXZ 51SMC 51LDS 51MNL 断层距/km 188.7 190.9 191.4 211.5 222.2 249.2 262.2 272.9 278.5 300.4 表 3 放大系数的统计参数
Table 3. Statistical parameter of amplification factor
自振周期/s 1 2 3 均值 1.012 1.229 1.701 方差 0.002 0.014 0.063 -
贺秋梅, 李小军, 张江伟等, 2014.某高温气冷堆核电厂结构地震反应分析.震灾防御技术, 9(3):454-461. doi: 10.11899/zzfy20140312 胡聿贤, 2006.地震工程学.北京:地震出版社. 李宏男, 2013.地震工程学.北京:机械工业出版社. 梁炯丰, 王俭宝, 顾连胜等, 2013.直接基于位移的钢框架结构抗震设计.四川建筑科学研究, 39(3):148-151 http://www.cnki.com.cn/Article/CJFDTOTAL-GCLX201007033.htm 刘启方, 袁一凡, 金星等, 2006.近断层地震动的基本特征.地震工程与工程振动, 26(1):1-10. http://www.cnki.com.cn/Article/CJFDTOTAL-DGGC200601000.htm 冉志杰, 杨歧焱, 周月玲, 孙丽娜等, 2012.唐山丰南M4.1级地震强震记录分析.震灾防御技术, 7(4):367-376. doi: 10.11899/zzfy20120404 吴泽玉, 张清晓, 2012.考虑竖向地震作用的高桥墩P-Δ效应分析.工程抗震与加固改造, 34(3):40-43. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=gckz201203009&dbname=CJFD&dbcode=CJFQ 谢俊举, 温增平, 高孟谭等, 2010.2008年汶川地震近断层竖向与水平向地震动特征.地球物理学报, 53(8):1796-1805. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWX201008006.htm 于海英, 王栋, 杨永强, 卢大伟等, 2008.汶川8.0级地震强震动特征初步分析.震灾防御技术, 3(4):321-336. doi: 10.11899/zzfy20080401 袁一凡, 田启文, 2012.工程地震学.北京:地震出版社. 赵国辉, 刘健新, 2008.汶川地震桥梁震害分析及抗震设计启示.震灾防御技术, 3(4):363-369. doi: 10.11899/zzfy20080405 中华人民共和国国家标准, 2010.建筑抗震设计规范 (GB 50011-2010).北京:中国建筑工业出版社. 周锡元, 徐平, 王国权, 闫维明, 2006.1999年台湾集集地震近断层竖向与水平反应谱比值的研究.地震地质, 28(3):325-335. http://www.cnki.com.cn/Article/CJFDTOTAL-DZDZ200603000.htm Ambraseys N. N., Douglas J., 2003. Near-field horizontal and vertical earthquake ground motions. Soil Dynamics and Earthquake Engineering, 23(1):1-18. doi: 10.1016/S0267-7261(02)00153-7 Niazi M., Bozorgnia Y., 1991. Behavior of near-source peak horizontal and vertical ground motions over SMART-1 array, Taiwan. Bulletin of the Seismological Society of America, 81(3):715-732. https://www.researchgate.net/publication/277855886_Behavior_of_near-source_peak_horizontal_and_vertical_ground_motions_over_SMART-1_Array_Taiwan